Low clouds over Monterrey backed up against the foothills of the Sierra Madre Oriental
After taking care of all the exit paperwork at San Luis Potosi, I preflight the airplane and call US Customs in Laredo. I report my expected time of arrival and they ask if I submitted my information through eAPIS. Yes, I did that before I started the trip. Now at this point, this would have been a good time for Laredo Customs to tell me that the Laredo airport was closed but they just accepted my arrival notice and said nothing about it.
We depart and climb to our cruise altitude of 11,500 feet. The first half of the trip is over high desert and there isn't much to look at. The only town of any size is Matehuala. I am able to talk with Monterrey Center though. Monterrey Center informs me that the Laredo airport is closed. I am certain I am not hearing this right and ask them to repeat. Laredo airport is closed from 1900Z to 2100Z. Z is for Zulu which means Greenwich Mean Time which is the universal aviation time used in all parts of the world. The use of this system simplifies things for flights that cross multiple time zones. For the rest of us it is just confusing. To convert Central time to Zulu time you use military time and add 6 hours unless daylight savings time is in effect then you add 5 hours. So 2100Z is 3:00 pm. I have a good tailwind so will be arriving earlier than expected, around 3:15 pm. So that should work.
I am not able to give Monterrey DME distances from Monterrey because the radio station is behind the mountains. They hand me off to Monterrey Approach way too soon. I'll have to consider that next time and mark off some reporting points. One very prominent reference point would be Cerro El Potosí (24.867°N 100.233°W), the tallest mountain in the Sierra Madre Oriental mountain range and directly on my route 55nm south of Monterrey. It was capped with snow. I was able to contact approach after this but still not receiving the DME signal. Approach gives me an update on the airport closure. It is now closed until 2130Z for an airshow. Now I'll be arriving too soon so I reduce my speed.
Upon arriving at the Sierra Madre Oriental, I can see the low clouds backed up against the foothills as anticipated. The mountains are rugged and beautiful. One peak has a hole penetrating through it. After crossing the Monterrey airport I begin a slow descent into Laredo. I am handed off the the Nuevo Laredo controller. I had planned to fly directly to Laredo but the Nuevo Laredo controller wants me to fly over his airport first so I make an adjustment. On reaching Nuevo Laredo, the controller hands me over to Laredo tower. I am two minutes early and the tower instructs me to remain clear of Class D airspace. I wasn't sure exactly where that was since I am using a Mexican sectional and it doesn't depict the Class D airspace, so I just remain on the Mexican side. As it turns out, the Class D airspace for Laredo has a 5 NM radius except that it doesn't appear to extend across the border (the airport is close to the border) and extends to an altitude of 3000 feet. Two minutes later I am cleared to land on 17L.
Laredo International Airport